random movement of microscopic particles suspended in a fluid, caused by bombardment of the particles by molecules of the fluid. First observed in 1827, it provided strong evidence in support of the kinetic theory of molecules

a semiconductor device, having three or more terminals attached to electrode regions, in which current flowing between two electrodes is controlled by a voltage or current applied to one or more specified electrodes. The device is capable of amplification, etc, and has replaced the valve in most circuits since it is much smaller, more robust, and works at a much lower voltage

the property of an electric circuit as a result of which an electromotive force is created by a change of current in the same circuit (self-inductance) or in a neighbouring circuit (mutual inductance). It is usually measured in henries